Heat exchangers can be used in climate control systems to transfer heat between warm and cool air streams flowing through different ducts of the system. For example, a heat exchanger can be used to transfer heat between an exhaust air stream flowing through an exhaust air duct and a supply air stream (e.g., return air and/or outside air) flowing through a supply air duct. This concept is generally referred to as heat recovery. The exhaust air stream and supply air stream will typically be at different temperatures. For example, when a climate control system is being used for heating a building, the exhaust air stream will be relatively warm and the supply air stream will be relatively cool. In this situation, a heat exchanger can be used to transfer heat from the exhaust air stream to the supply air stream to heat the supply air stream before it is fully heated by a heater. In this way, heat is recovered from the warm exhaust air and used to warm the incoming supply air. Conversely, when a ventilation system is used for cooling a building, the exhaust air stream will be relatively cool and the supply air stream will be relatively warm. In this situation, the heat exchanger can be used to transfer heat from the supply air stream to the exhaust air stream to cool the supply air stream before it is further cooled by an air conditioner. In this way, heat is moved from the incoming supply air stream to the exhaust air stream to pre-cool the incoming supply air stream. Some ventilation systems are used for both heating and cooling a building over the course of a year.